conditional maxInstances

[holmerjohn]

I have still never been able to make this fail a test in Jest, but when run within the context of a sls deploy the configuration-template-update.yml file can be malformed if the maxInstances valus is not set for the function. This PR checks for the existence of the property on the funcObject and then maps the value over if it is found. This has been tested to deploy a project that contains multiple functions, some of which include maxInstances, and some do not. The deployed functions in the console that do not declare a maxInstances are unrestricted, and those that do are restricted as configured in the serverless.yml

An example of the error output from the malformed yml:

Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Compiling function "http-config"...
Serverless: Compiling function "pubsub-echo"...
Serverless: Compiling function "pubsub-refresh-auth"...
Serverless: Uploading artifacts...
Serverless: Artifacts successfully uploaded...
Serverless: Updating deployment...
 
  Error --------------------------------------------------
 
  Error: Error parsing configuration: could not determine a constructor for the tag tag:yaml.org,2002:js/undefined
   in 'string', line 21, column 21:
            maxInstances: !<tag:yaml.org,2002:js/undefined> ''

[holmerjohn]

This addresses newly created Issue #198

[medikoo]

@holmerjohn great thanks for that fix.

Can you update branch with master and confim CI passes? We've just upgraded package with better automated maintanance rules.

[holmerjohn]

@medikoo merged master and fixed the prettier file. ci passes. thanks

[medikoo]

Thank you @holmerjohn !